POP star Britney Spears is suing a US magazine for £11.2m over a story that she and her husband Kevin Federline made a sex tape.

But a spokesman for Us Weekly said: "We have a very credible source and we stand by our story."

According to the lawsuit, the article was published in October in the magazine's Hot Stuff column and claimed that Spears and her husband feared the release of a secret sex tape, which they had viewed with their lawyers.

The article stated that Spears gave a copy of the tape to the lawyers on September 30 and that she and her husband were "acting goofy the whole time" while watching the video.

But her lawyers said: "There was no laughter, disgust or goofy behaviour while watching the video in the company of lawyers because they did not watch any video, and because there is no such video."

They said Spears went to court after Us Weekly refused her request for a retraction.

Spears and Us Weekly also tangled in February after the magazine published pictures of her honeymoon in Fiji.